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curios
Asked: 2020-11-01 16:03:21 +0800 CST

Xen Domain0 Has Network But DomainU does not

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After re-installing my domain 0, a guest VM (domain U) is no longer able to connect to the network.

I am using Ubuntu 20.4 on my Domain 0 with Xen 4.11. I am able to successfully connect to internet on this.

cat /etc/netplan/config.yaml

  version: 2
  renderer: networkd

  ethernets:
    enp0s25:
      dhcp4: false
      dhcp6: false
  bridges:
    xenbr0:
      interfaces: [enp0s25]
      addresses: [192.168.1.99/24]
      gateway4: 192.168.1.1
      mtu: 1500
      nameservers:
        addresses: [1.1.1.1]
      parameters:
        stp: true
        forward-delay: 4
      dhcp4: no
      dhcp6: no

#ip route list:

default via 192.168.1.1 dev xenbr0 proto static 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 linkdown

from .cfg file for Domain U:

vif         = [ 'ip=192.168.1.102 ,mac=00:16:3E:75:C2:D9,bridge=xenbr0' ]

In Domain U: $ping 8.8.8.8

PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
^C
--- 8.8.8.8 ping statistics ---
11 packets transmitted, 0 received, 100% packet loss, time 253ms

I'm kind of stumped, this Domain U was previously able to connect to the network before I had to re-install this domain 0. What steps or troubleshooting do you recommend to get this to connect?

Possible clues: the domain U was previously on a different physical hypervisor, so in addition to a new domain 0 it's a new NIC. A freshly installed domain U using xen-create-image is also not able to connect. This leads me to conclude the issue is with my setup with domain 0.

Thanks in advance for your help!

xen ubuntu networking bridge netplan

1 Answers

  1. Resolved:

    I was able to resolve this by re-installing domain0. The only setting I changed vs the domain0 that was getting the error was this time I did not include docker in the installed packages list.

    For some context about why I had two different kinds of virtualization: I am transitioning to containers, but still have some services in VMs. I wanted to be able to keep my old services active while transitioning. The workaround I'm choosing is to create a new VM, and install docker on that.

    I can only conclude that the docker bridge was in someway interfering with the bridge I had set for the VMs. Perhaps docker is not compatible with xen hypervisor? If anyone has further context about this I'm very curious.

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